Add DidFinalizeCycle event, add more tests for cyclic nested queries

[MichaReiser]

This adds a new DidFinalizeCycle event that Salsa emits when the outermost cycle head is finalized.

This PR also adds two new tests:

1. A test where the nested cycle converges before the outer cycle converges (it can be finalized before the outer cycle
2. A test where the nested cycle never converges, but the outer cycle only depends on it in the first iterations.

I haven't yet decided on what the expectation is for both those cases, but I thought it's worth adding tests

[netlify]

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[codspeed-hq]

CodSpeed Performance Report

Merging this PR will not alter performance

_{Comparing MichaReiser:micha/no-early-converge (a40ea13) with master (103fa51)}

Summary

✅ 13 untouched benchmarks